Alonzo Church (1903-1995)was an American mathematician and logician who made groundbreaking contributions to mathematical logic, recursion theory, and computer science. Church's Thesis is a statement about the notion of "effective" or "mechanical" or "computable" procedures, so before stating the thesis itself, we shall first give an explanation of what "effective" or "mechanical" or "computable" procedures are. These three terms will be considered synonymous and for simplicity we shall use "effective" throughout this article. In essence, an effective procedure is a procedure which, in principle, could be carried out by a human being with nothing more than pencil and paper in a finite number of steps with no insight or ingenuity on the part of the human being. That is to say, the human being need only follow, without deviation, a finite fixed set of instructions to obtain the result of the procedure. Such a procedure...